Destroying vegetation with haloalkenyl disubstituted thionocarbamates



United States Patent 3,224,864 DESTROYING VEGETATION WITH HALOALKE- NYL DISUBSTITUTED THIONOCARBAMATES Philip C. Hamm, Webster Groves, Mo., and John J. DAmico, Charleston, W. Va., assignors to Monsanto Company, a corporation of Delaware No Drawing. Filed Sept. 26, 1962, Ser. No. 226,436 Claims. (Cl. 71-25) This application is a continuation-in-part of copending application Serial No. 721,360, filed March 14, 1958, now abandoned.

The present invention relates to halogen substituted alkenyl esters of thionocarbamic acids, to herbicidal compositions containing the new compounds and to methods of destroying vegetation using these herbicidal compositions.

The new compounds contain the nucleus Where A is a halogen substituted alkenyl group containing less than five carbon atoms. By halogen substituted alkenyl group is meant an open chain unsaturated radical having one double bond and at least one halogen substituent. The dangling valences on the nitrogen may be satisfied by a Wide variety of non aromatic organic radicals but not by hydrogen. In other words, the nitrogen atom should be linked to three carbon atoms. For example, the dangling valances on the nitrogen may be satisfied by members of the class consisting of open chain saturated and unsaturated non aromatic radicals and divalent aliphatic radicals which, with the nitrogen, constitute a heterocyclic group. By non aromatic radicals are meant radicals in which the carbon attached to the nitrogen of the above nucleus is not part of an aromatic ring.

Examples of the new compounds are represented by the 2-chloroallyl, 2-bromoallyl, 3-chlorallyl, 3-iodoallyl, 2- fiuoro-3-chloroallyl, 3-bromo-2-butenyl, 3-chloro-2-butenyl, 2,3-dichloroallyl, 3,3-dichloroallyl, 2,3-dichloro-2-butenyl, 2,3-diiodo-2-butenyl, 2,3-dibromoallyl, 2,3-dichloro- 4-bromobutenyl and 2,3,3-trichloroallyl esters of the following thionocarbamic acids: dimethyl, diethyl-, dibutyl-, dipropyl-, diallyl-, diisopropyl-, diisobutyl-, (allyl)isopropyl-, di(methoxyethyl)-, (methyl)cyclohexyl-, (ethyl)cyclohexyl-, (2-cyclohexenyl)isopropyl-, (2-cyanoethyl)isopropyl-, (Z-chloroallyl)isopropyl-, (2-chloroallyl)-3-methoxypropyl-, di(2-phenoxyethyl)-, (ethyl)2 phenoxyethy1-, di(2-chloroallyl)-, (ethyl)vinyloxyethyl-, (ethyl)-isopropoxypropyl-, di(methoxypropyl)- and di(ethoxypropyl)-thionocarbamic acids, 4-morpholinecarbothionic acid, l-pyrrolidinecarbothionic acid, 4-phenyl-l-piperazinecarbothionic acid, l-piperidinecarbothionic acid, Z-methyl-lpiperidinecarbothionic acid, S-ethyl-Z-methyl-l-piperidinecarbothionic acid, 5-ethyl-3-methyl-l-piperidinecarbothionic acid, 2,4,6-trimethyl-1-piperidinecarbothionic acid, 2,6-dimethylmorpholinecarbothionic acid and l-hexamethyleniminecarbothionic acid.

The compounds may be prepared by several methods. The following examples illustrate the preparation but the invention is not limited thereto.

Example 1 To 151.7 parts by weight 1.0 mole) of diethylthiocarbamyl chloride in about 440 parts by weight of dry benzene was added in one portion 92.6 parts by weight (1.0 mole) of 2-chloro-2-propen-1-ol. The stirred mixture was then heated at refiux for 18 hours, cooled to C. and the impurities filtered off. The benzene was removed by distillation. Vacuum distillation of the residue gave a 24.2% yield of 2-chloroallyldiethylthionocarba- "ice mate, B.P. 134136 C./17 mm. Analysis gave 6.9% nitrogen as compared to 6.7% calculated for A somewhat higher yield was obtained by heating for 5 hours at 95-98 C. a mixture of 92.6 parts by weight (1.0 mole) of 2-chloro-2-propen-1-ol, 151.7 parts by weight 1.0 mole) of diethylthiocarbamyl chloride, 138 parts by weight of potassium carbonate and about 345 parts by weight of heptane. The mixture was then cooled to 25 C., filtered and the heptane removed by distillation in vacuo. The yield was 47.8% of a dark amber oil analyzing 6.6% nitrogen, 15.0% sulfur and 17.4% chlorine as compared to 6.7% nitrogen, 15.4% sulfur and 17.1% chlorine calculated for C H CINOS.

The most satisfactory and preferred procedure was carried out as follows: To a stirred solution of 27.1 parts by weight (0.255 mole) of sodium carbonate .in 200 parts by Weight of Water was added 47.3 parts by weight (0.5) mole) of monochloracetic acid to form a solution having a pH of 8. The addition was carried out at a temperature of 10-20" C. over a 10 minute period. Stirring was continued for 15 minutes and then 103.4 parts by weight (0.5 mole) of potassium 2-chloroallylxanthate was added in one portion. The endothermic reaction which first set in caused a drop in temperature from 23 to 15 C. The exothermic reaction which followed caused a temperature rise to 38 C. over a 20 minute period. The reaction mixture was stirred for one and one-half hours at 1539 C., then cooled to 10 C. and 43.9 parts by weight (0.6 mole) of diethylamine added in one portion. The heat of reaction caused a temperature rise to 36 C. in 5 minutes. The product was stirred for 5 hours while maintaining the temperature at 25-30 C. The top organic layer which separated was heated in vacuo (14 mm.) at a maximum temperature of 60 C. for 3 hours and then filtered. The 2-chloroallyl diethylthionocarbamate Was obtained in 77.5% yield as an amber liquid. The product was distilled collecting the fraction B.P. 83-84 C./ 2 mm. Analysis gave 6.5% nitrogen, 15.4% sulfur and 17.3% chlorine as compared to 6.7% nitrogen, 15.4% sulfur and 17.1% chlorine calculated for C H CINOS.

Example 2 In this example 92.6 parts by weight (1.0 mole) of 2-chloro-2-propen-1-ol was added in one portion to a stirred solution of 179.7 parts by weight (1.0 mole) of dipropylthiocarbamyl chloride in about 300 parts by weight of pyridine. The mixture was then heated at 85-90 C. for 24 hours, cooled to 25 C. and 400 parts by weight of water added. Stirring was continued for 15 minutes and the reaction mixture then extracted with about 360 parts by weight of ethyl ether. The ether solution was washed With water until neutral to litmus, dried over sodium sulfate and the ether removed in vacuo. The residue was distilled in vacuo, the fraction B.P. 142-144" C./6 mm. being collected. The 2-chloroallyl dipropylthionocarbamate was obtained in 31.9% yield and analyzed 6.1% nitrogen, 13.5% sulfur and 15.1% chlorine as compared to 5.9% nitrogen, 13.6% sulfur and 15.0% chlorine calculated for C H ClNOS. The same compound was obtained in yield via the xanthate by the procedure described in the third paragraph of Example 1. The reactants and proportions were 47.3 parts by weight of monochloracetic acid neutralized with 27.1 parts by weight of sodium carbonate in 200 parts by weight of water, 103.4 parts by weight of potassium 2-chlorallylxanthate and 60.8 parts by Weight of dipropylamine.

Example 3 A sample of 2-chloroallyl dimethylthionocarbamate Was successfully prepared in a yield of 13.4% employing '2 a an excess of the alcohol but no other solvents. Dimethylthiocarbamyl chloride, 123.6 parts by weight (1.0 mole), was added to 386 parts by weight of 2-chloro-2-propen-1- 01 in small portions and the mixture then heated at 75 85 C. for 24 hours. After cooling to 25 C. the product was filtered to remove small amounts of impurities and the excess alcohol removed by distillation (B.P. 60-63 C./28 mm.). The residue was filtered to remove impurities and then distilled in vacuo. The fraction of 2- chloroallyl dimethylthionocarbamate boiling at 12S-126 C./ 12 mm. was collected as an amber liquid and analyzed 7.3% nitrogen as compared to 7.8% calculated for C H ClNOS. Preparation via the xanthate by the procedure described in the third paragraph of Example 1 gave an 80.5% yield. The reactants and proportions were 47.3 parts by weight of monochloracetic acid neutralized with 27.1 parts by weight of sodium carbonate in 200 parts by weight of water, 103.4 parts by weight of potassium Z-chlorallylxanthate and 108 parts by weight of 25% aqueous dimethylamine. Analysis gave 7.5% nitrogen, 18.1% sulfur and 20.1% chlorine. The values calculated for sulfur and chlorine were 17.9% sulfur and 19.7% chlorine.

Example 4 Substituting 77.5 parts by weight of dibutylamine for the 60.8 parts by weight of dipropylamine used in the second part of Example 2 gave an 81.4% yield of 2-chloroallyl dibutylthionocarbamate, an amber oil which contained 5.8% nitrogen and 12.2% sulfur compared to 5.3% nitrogen and 12.2% sulfur calculated for C H CINOS.

Example 5 To a stirred solution comprising 92.5 parts by weight (1.0 mole) of 2-chloro-2-propen-1-ol, 106 parts by weight (1.0 mole) of sodium carbonate and 400 ml. of benzene there was added in one portion 132.6 parts by weight (0.8 mole) of 4-morpholinothiocarbamyl chloride and the mixture then heated at refluxing temperature for 5 hours. After cooling to 25 C., 300 ml. of water was added, stirring continued for minutes and the reaction mixture then filtered. The top benzene layer was separated, Washed with water until neutral to litmus and dried over sodium sulfate. The benzene and excess alcohol were removed in vacuo at a maximum temperature of 8090 C./12 mm. The product was cooled to C. and after standing for 24 hours, a small amount of impurities were removed by filtration. 2-chloroallyl 4-rnorpholinecarbothionate was obtained in 61% yield as an amber oil analyzing 6.8% nitrogen compared to 6.3 cal- U culated for CgHlZClNOZS.

Example 6 In the procedure of Example 5, 31.8 parts by weight (0.25 mole) of cisand trans-2,3-dichloro-2-propen-l-ol,

Example 7 To 23.7 parts by weight (0.25 mole) of chloracetic acid was added 13.6 parts by weight (0.128 mole) of sodium carbonate dissolved in 200 ml. of water to give a solution having a pH of about 8. The solution was stirred for 15 minutes at 2025 C. and then 60.3 parts by weight (0.25 mole) of potassium 3,3-dichloroallylxanthate added in one portion at 23 C. The temperature dropped at first to 17 C. and then rose to a maximum of 31 C. After stirring the reaction mixture for one and one-half hours, it was cooled to 10 C. There was then added in one portion, 34 parts by weight (0.3 mole) of N-methyl-N-cyclohexylamine, causing the temperature to rise to 36 C. Stirring was continued for 5 hours and the reaction mixture then extracted with 400 ml. of ethyl ether. The ether extract was washed with two 200 ml. portions of Water, then with 200 ml. of dilute hydrochloric acid solution followed by water until neutral to litmus. After drying over sodium sulfate the ether was removed in vacuo at a maximum temperature of 60 C./12 mm. 3,3-dichloroallyl N-cyclohexyl-N-methylthionocarbamate was obtained in 57% yield as an amber liquid. Analysis gave 4.0% nitrogen compared to 4.9% calculated for C11H1I1C12NOS.

Employing the same reaction conditions and replacing N-methyl-N-cyclohexylamine with an equi-molar amount, respectively, of N-ethyl-N-cyclohexylamine, N-propyl-N- cyclohexylamine and N-isopropyl-N-cyclohexylamine, further examples were prepared possessing the following physical properties:

Example 8 3,3-dichloroallyl N-cyclohexyl-N-ethylthionocarbamate, an amber liquid, in 46% yield.

Example 9 3,3 dichloroallyl N cyclohexyl-N-propylthionocarbamate, an amber liquid, in 55.5% yield. Analysis gave 4.0% nitrogen compared to 4.5% calculated for C H Cl NOS Example 10 3,3-dicl1loroallyl N-cyclohexyl-N-isopropylthionocarbamate, an amber liquid, in 36% yield. Analysis gave 3.7% nitrogen compared to 4.5% calculated for C H Cl NOS.

Example 11 Substituting potassium 2-chloroallylxanthate for the xanthate in Example 7, 2-chloroallyl N-cyclohexyl-N- methylthionocarbamate was obtained as an amber oil in 61.5% yield. Analysis gave 5.4% nitrogen and 13.0% sulfur compared to 5.6% nitrogen and 12.9% sulfur calculated fOI CnHmClNOS.

Similarly replacing N-methyl-N-cyclohexylamine with an equi-molar amount, respectively, of N-ethyl-N-cyclohexylamine, N-propyl-N-cyclohexyla-mine and N-isopropyl-N-cyclohexylamine, further examples were prepared possessing the following physical properties:

Example 12 2-chloroallyl N-cyclohexyl-N-ethylthionocarbamate, an amber liquid, in 38.2% yield. Analysis gave 5.0% nitrogen and 13.7% chlorine compared to 5.3% nitrogen and 13.5% chlorine calculated for C H ClNOS.

Example 13 2-chloroally1 N-cyclohexyl-N propylthionocarbamate, an amber oil, in 61% yield. Analysis gave 5.1% nitrogen and 12.3% chlorine compared to 5.1% nitrogen and 12.8% chlorine calculated for C H ClNOS.

Example 14 2-chloroallyl N-cyclohexyl N isopropylthionocarbamate, an amber liquid, in 47.8% yield. Analysis gave 4.6% nitrogen compared to 5.1% calculated for C H ClNOS.

7 Example 15 To a stirred slurry comprising 32 parts by weight (0.335 mole) of 2-chloro-2-propen-1-ol, 35 parts by weight (0.25 mole) of potassium carbonate and 300 ml. of heptane was added in one portion, with stirring, 37.4 parts by weight (0.25 mole) of pyrrolidinylthiocarbamoyl chloride. The stirred reaction mixture was heated at refluxing temperature for 6 hours and then filtered hot (6070 C.) to remove any insoluble impurities. The solvent was removed in vacuo at a maximum temperature of 90 C./12 mm. 2-chloroallyl 1-pyrrolidinecarbothionate was obtained in 72% yield as an amber liquid. Analysis gave 6.9% nitrogen, 15.4% sulfur and 17.2% chlorine com- Example 1 6 Example 18 3-chloroallyl 1-pyrrolidinecarbothionate, liquid, in 72.2% yield.

Example 19 2,3-dichloroallyl l-pyrrolidinecarbothionate, an amber liquid, in 99% yield.

an amber Example 20 A charge consisting of 88.9 parts by weight (0.5 mole) of dipropylthiocarbamyl chloride, 69.1 parts by weight (0.5 mole) of potassium carbonate and 63.5 parts by weight 0.5 mole) of cisand trans-2,3-dichloro-2-propen- 1-ol in 400 ml. of heptane was heated at refluxing temperature for hours and then filtered hot. The solvent was removed in vacuo at a maximum temperature of 80- 90 C./l-2 mm. and the product allowed to stand at room temperature for 24 hours. A small amount of impurities were removed by filtration whereupon cisand trans-2,3- dichlororoallyl dipropylthionocarbamate was obtained as an amber liquid in 73.1% yield. Analysis gave 5.2% nitrogen, 10.8% sulfur and 26.8% chlorine compared to 5.2% nitrogen, 11.9% sulfur and 26.2% chlorine calculated for CIOH17C1ZNOS.

Example 21 The dipropylthiocarbamyl chloride was substituted by 100 parts by weight (0.5 mole) of 90% diisopropylthiocarbarnyl chloride in the procedure of Example 20. The oil, upon standing 24 hours at 2530 C. deposited a solid which was removed by filtration and recrystallized from ethyl alcohol. The resulting white solid melted at 104105 C. and was obtained in 32.4% yield. Elemental and infrared spectra analyses confirmed the product was cis-2,3-dichloroallyl diisopropylthionocarbamate.

Additional solid deposited after standing another 24 hours. After recrystallization from ethyl alcohol the white solid so deposited melted at 8788 C. and was obtained in 17% yield. Elemental and infrared spectra analyses indicated the product was trans-2,3-dichloroallyl diisopropylthionocarbamate: nitrogen, 5.2%; sulfur, 11.9% and chlorine, 26.2%.

Example 22 A mixture of 16.2 parts by weight (0.1 mole) of 2,3,3- triehloro-Z-propen-l-ol, 13.8 parts by weight (0.1 mole) of potassium carbonate and 200 ml. of heptane was prepared and 21 parts by weight (0.1 mole) of dibutylthiocarbamyl chloride added in one portion. The reactants were heated at refluxing temperature for 6 hours, then filtered hot and the hep'tane removed in vacuo at a maxi mum temperature of 90 C./12 mm. 2,3,3-trichloroallyl dibutylthionocarbamate was obtained in 99% yield as an amber oil. Analysis gave 4.2% nitrogen and 9.3% sulfur compared to 4.2% nitrogen and 9.6% sulfur calculated fOI' C H CI NOS.

Other examples prepared by the same procedure as in Example 22 but substituting the appropriate reactants are summarized in tabular form below. All were amber oils:

TABLE I Example Product Yield,

No. percent Cisand trans-2,3-dichloroallyl l-hexamethyl- 74. 5

eniminecarbothionate. 2,3,3-trichloroallyl l-hexamethylenirninc-carbo- 79.4

thionate. 2,3,3-trichloroallyl diothylthionocarbamate 75. 2 2,3,3-trichloroallyl dipropylthionocarbamat-e 84. 1 2,3,3-trichloroallyl 1-pyrrolidinecarbothionate 68. 6 2,3,3trichloroallyl dimethylthionocarbamate- 82. 0 2,3,3-trichloroallyl diisopropylthionocarbamate 96. 0 2-chloroallyl l-hexamethyleuiminecarbothiouate. 95.7 3-chloroallyl l-hcxamethyleniminecarbothionate. 91. 5 2,3,3-trichloroallyl Ncyclohexyl-N-ethylthiono- 96.8

carbamate. Cisand trans-2,8'dichloroallyl N-cyclohexyl-N- 71.0

ethylthionocarbarnate.

Table 11 illustrates the pre-emergent herbicidal activity of typical disubstit-uted haloalkenyl thionocarbamates. The ester was emulsified in water and the emulsion applied as a spray. In this manner, the active ingredient at the dosage indicated was applied to the ground of seeded plots before the grass or other plants emerged:

TAB LE II Active Ingredient Lbs/acre Results Observed 2-chloroallyl dietbylthiouocarbamate 2-eh1oroa1lyl dipropylthionocarbamate Cisand trans-2,3-dichloroallyl dipropylthionocarbamate- Cis-2,3dichlor0allyl diisopropylthionocarbamate Trans-2,3dich1oroa1lyl diisopropylthionocarbamate 3,3-dichloroallyl N-cyclohexyl-N-isopropylthionocarbamate.

Severe phytotoxicity to wild oat, brome grass, rye grass, buckwheat, mustmd (radish), foxtail, barnyard grass and crab grass; moderate phytotoxicity to cotton and pigweed.

Severe phytotoxicity to wild oat, brome grass, rye grass, buckwheat, beet-sugar, foxtail, barnyard grass, crab grass and pigweed; moderate phytotoxicity to cotton.

Severe phytotoxicity to wild oat, brome grass, rye grass, cotton and barnyard grass; moderate phytotoxicity to ioxtail and pigweed.

Severe phytotoxicity to wild oat, rye grass, barnyard grass, crab grass,

pigweed and sorghum.

Severe phytotoxicity to brome grass; moderate phytotoxicity to wild buckwheat.

Severe phytotoxiclty to Wild oat, brome grass, rye grass, foxtail, crab grass, pigweed and sorghum; moderate phytotoxicity to morning glory.

Severe phytotoxicity to wild oat, brome grass rye grass, crab grass, mixture of grasses and sorghum; moderate phytotoxicity to beet-sugar and tomato.

Severe phytotoxicity to tomato; moderate phytotoxiclty to a mixture of grasses, wild oat, brome grass and rye grass.

Severe phytotoxicity to a mixture of grasses, wild oat, rye grass, foxtail and crab grass; moderate phytotoxicity to morning glory, brome grass, wild buckwheat, tomato and mixture of broadleai' plants.

Severe phytotoxicity to a mixture of grasses, wild oat, brome grass, rye

grass, foxtail, crab grass, pigweed and'sorghurn.

Results Observed Active Ingredient Lbs/acre 3,3-dichloroallyl N-eyclohexyl-N-ethylthionocarbamate 3 ,3-dichloroallyl N-cyelohexyl-N-methylthionocarb amate- 3,3-dich loroallyl N -cyclohexyl-N-prop ylthionocarb amate-. 25

2-chloroallyl N -cyclohexy1-N-methylthionocarbamate 25 2-chloroallyl N -cyclohexyl-N-ethylthionocarbamate 25 2-chloroallyl N-cyclohexyl-N-propylthi0nocarbamate 25 2-chloroallyl N-cyclohexyl-N-isopropylthionocarbamate 25 2,3 ',3-trlchloroallyl N-eyclohexyl-N-ethylthionocarbamate 25 01sand trans-2,3-diohloroallyl N-cyclohexyl-N-ethylthion0- 25 carbamate. Cisand trans-2,3-dichl0roallyl l-hexamethyleniminecarbo- 25 thionate. 2,3,3-trichloroallyl l-hexamethyleniminecarbothionate 25 2 chloroallyl l-pyrrolidinecarbothionate 25 3,3-dlchloroallyl l-pyrrolidinecarbothionate 25 3-chloro-2-butcnyl l-pyrrolidiuecarbothionate 25 2,3,3-trichlor0allyl diethylthionocarbamate 25 2,3,3-trlchloroallyl dipropylthionocarbamate 25 3-chloroallyl l-pyrrolidinccarbothlonate 25 2,3-dichloroallyl l-pyrrolidinecarbothionate 25 2,3,3-trichloroallyl l-pyrrolldinecarbothionate 25 2,3,3-trichloroallyl dibutylthionocarbamate 25 2,3,3-trichloroallyl dimethyltliionocarbamate 5 2,3,3trichl0r0allyl diisopropylthionocarbamate 5 2-chloroallyl l-hexamethyleniminecarbothionate 5 3-chloroallyl l-hexamethyloniminecarbothionate 5 Severe phytotoxicity to a mixture of grasses, wild oat, rye grass, foxtail,

crab grass and sorghum.

Severe phytotoxicity to a mixture of grasses, wild oat, rye grass, crab grass, pigweed, wild buckwheat and sorghum; moderate phytotoxicity to morning glory and mixture of broadleaf plants.

Severe phytotoxicity to a mixture of grasses, wild oat, foxtail, crab grass, pigweed and sorghum; moderate phytotoxicity to pigweed and wild buckwheat.

Severe phytotoxicity to a mixture of grasses, wild oat, brome grass, rye grass, crab grass, pigweed, wild buckwheat and sorghum; moderate phytotoxicity to mixture of broadleaf plants, beet-sugar and tomato.

Severe phytotoxicity to a mixture of grasses, mixture of broadleaf plants, wild oat, brome grass, rye grass, beet-sugar, ioxtail, crab grass, pigweed, wild buckwheat and sorghum; moderate phytotoxicity to morning glory, soybean and tomato.

Severe phytotoxicity to wild oat, mixture of grasses, foxtail, crab grass and sorghum; moderate phytotoxicity to brome grass, beet-sugar and pigwee Severe phytotoxicity to wild oat, crab grass, pigweed and wild buckwheat;

moderate phytotoxicity to mixture of grasses and rye grass.

Severe phytotoxicity to crab grass; moderate phytotoxicity to wild cat.

Severe phytotoxicity to a mixture of grasses, wild oat, rye grass, foxtail,

crab grass, pigweed and sorghum.

Severe phytotoxicity to morning glory, beet-sugar, crab grass, pigweed and sorghum; moderate phytotoxicity to rye grass and tomato.

Severe phytotoxieity to crab grass and pigweed; moderate phytotoxicity to bcet-sugar.

Severe phytotoxicity to rye grass, crab grass and pigwced; moderate phytotoxicity to mixture of grasses, mixture of broadleaf plants, brome grass, beet-sugar, wild buckwheat and sorghum.

Severe phytotoxicity to morning glory, wild oat, rye grass, foxtail, crab grass, pigweed, tomato and sorghum; moderate phytotoxicity to buckwheat, radish and beet-sugar.

Severe phytotoxicity to mixture of grasses, brome grass, beet-sugar, pigweed, soybean and sorghum; moderate phytotoxicity to mixture of broadleaf plants, wild oat, ioxtail, crab grass and wild buckwheat.

Severe phytotoxicity to rye grass, ioxtail, crab grass, pigweed, soybean and tomato; moderate phytotoxicity to beet-sugar and sorghum.

Severe phytotoxicity to morning glory, rye grass, beet-sugar, ioxtail, crab grass, pigweed and sorghum; moderate phytotoxicity to wild oat.

Severe phytotoxicity to pigweed; moderate phytotoxicity to mixture of grasses, mixture of broadleai plants, morning glory, wild cat, brome grass, rye grass, beet-sugar, crab grass and tomato.

Severe phytotoxicity to wild oat, brome grass, rye grass, radish, beetsugar, foxtail, crab grass, pigwced, tomato and sorghum; moderate phytotoxicity to morning glory.

Severe phytotoxicity to brome grass, rye grass, ioxtail, crab grass, pigweed and sorghum; moderate phytotoxicity to wild oat.

Severe phytotoxicity to bromc grass; moderate phytotoxicity to pigweed.

Sever; phytotoxicity to soybean; moderate phytotoxicity to foxtail and cra grass.

Moderate phytotoxicity to wild oat, ioxtail and crab grass.

Severe phytotoxicity to a mixture of grasses, brome grass, rye grass, toxtail, crab grass, pigweed, wild buckwheat and sorghum; moderate phytotoxicity to wild oat.

Moderate phytotoxicity to brome grass, ioxtail and crab grass.

When tested at lower concentrations, 2-chloroallyl diethylthionocarbamate completely controlled grasses at one pound per acre and it was still very active on most grasses at one-half pound per acre.

An aqueous spray containing 0.5% of 2-chloroallyl diethylhionocarbamate was applied to the foilage of grass and to the foliage of bean and broadleaf plants. Severe phytotoxicity to grasses was observed.

The foregoing are only illustrative of the important new class herein defined which control vegetation although the amounts required for effective control will vary. Optimum activity is achieved with 2-chl-oroallyl esters represented by: 2-chloroallyl N-isopropyl-N-allylthionocarbamatc, 2-chloroallyl N-2-choroallyl N isopropylthionocarbamate, 2-chloroallyl N 2 chloroallyl N 3- methoxypropylthionocarbamatc, 2 chloroallyl diallylthionocarbamate, 2-chloroallyl 1-piperidinecarbothionate, 2 chloroallyl S-ethyI-Z-methyl-1-piperidinecarbothionate and 2-chlor-oallyl 5-ethyl-3-methyl-l-piperidinecarbothionate.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. The method of destroying vegetation which comprises applying thereto a phytotoxic amount of a composition containing as the essential active ingredient a compound of the structure where A is halogen substituted alkenyl containing less than five carbon atoms and the valences on the nitrogen are satisfied by organic radicals selected from the class consisting of lower alkyl, lower alkenyl, halogen substituted lower alkenyl, lower alkoxy substituted lower alkyl, lower alkenoxy substituted lower alkyl, phenoxy substituted ower alkyl, cyano substituted lower alkyl, cyclohexyl, cyclohexenyl, alkylene of four to eight carbon atoms inclusive, which with the nitrogen form an heterocyclic ring containing at least five but not more than seven ring members, and radicals which with the nitrogen form an heterocyclic ring of the group consisting of 4-phenylpiperazine, morpholine and 2,6-dirnethylmorpholine.

2. The method of destroying vegetation which comprises applying to germinating grass seedlings a phytotoxic amount of a composition containing as the essential active ingredient a compound of the structure s @N-ii-o-n where R represents alkylene of four to eight carbon atoms inclusive which with the nitrogen forms a heterocyclic ring containing at least five but not more than seven ring members and A represents chlorine substituted alkenyl containing less than five carbon atoms.

3. The method of destroying vegetation which comprises applying to germinating grass seedlings a phytotoxic amount of a composition containing as the essential active ingredient a halogen substituted 2-alkenyl ester of a thionocarbamic acid in which the alkenyl group conwhere R and R are lower alkyl and A is halogen substituted alkenyl containing less than five carbon atoms.

5. The method of destroying vegetation which comprises applying to germinating grass seedlings a phytotoxic amount of a composition containing as the essential active ingredient a compound of the structure where R and R are lower alkoxy substituted lower alkyl and A is chlorine substituted alkenyl containing less than five carbon atoms.

6. The method of destroying vegetation which comprises applying to germanting grass seedlings a phytotoxic amount of a composition containing as the essential ac tive ingredient a compound of the structure where R is lower alkyl, R is chlorine substituted ally] and A is chlorine substituted alkenyl containing less than five carbon atoms.

7. The method of destroying vegetation which comprises applying to germinating grass seedlings a phytotoxic amount of a composition containing as the essential ac tive ingredient a compound of the structure 8. The method of destroying vegetation which comprises applying to germinating grass seedlings a phytotoxic amount of a composition containing as the essential active ingredient a compound of the structure 9. The method of destroying vegetation which com prises applying to germanating grass seedlings a phytotoxic amount of a composition containing as the essential ac tive ingredient a compound of the structure 10. The method of destroying vegetation which comprises applying to germinating grass seedlings a phytotoxic amount of a composition containing as the essential active ingredient a compound of the structure References Cited by the Examiner UNITED STATES PATENTS 2,650,876 9/1953 Stewart 71-2.7 2,744,898 5/1956 Harman et al. -u 712.7 X 2,919,182 12/1959 Harman et al. 712.7 2,984,559 5/1961 DAmico 712.7 2,992,091 7/1961 Harman et a1. 7l2.6 3,066,021 11/1962 Beaver et al 71--2.6 3,078,153 2/1963 Harman et a1. 712.5

OTHER REFERENCES Tilles, I. Am. Chem. Soc., vol. 81, No. 3, pages 714 to 727 (page 718 particularly pertinent), Feb. 5, 1954.

LEWIS GOTTS, Primary Examiner. 

1. THE METHOD OF DESTROYING VEGETATION WHICH COMPRISES APPLYING THERETO A PHYTOTOXIC AMOUNT OF A COMPOSITION CONTAINING AS THE ESSENTIAL ACTIVE INGREDIENT A COMPOUND OF THE STRUCTURE 